397 
The pleurapophysis (fig. 8, »/) is more prominently marked than in Struthio; a low 
tuberosity represents the diapophysis (fig. 10, d); the interzygapophysial bar (fig. 11, 7) 
has gained breadth ; the interzygapophysial foramen (fig. 11, s) is well defined. 
On the under part of the centrum (fig. 10) the transverse preaxial articular concave 
tract is followed by a broad depression beyond. From this begins the medial ridge, which 
expands into the tuberous hypapophysis (iy). This is less produced than in the axis. 
The chief differences from the Ostrich, besides the shorter or broader and deeper 
proportions of the entire vertebra, are seen in the more distinct hypapophysis, the better- 
developed hyperapophyses (fig. 8, hp), and the more distinctly bifid character of the 
neural spine (figs. 9 & 11, ns). 
This spine rises a short way before it divides: a ridge extends from the fore and hind 
margins of each division, and defines the depression (for the insertion of elastic liga- 
ments) in front and behind the undivided base: this, at its summit, is not more than 
c FOURTH VERTEBRA (3 natural size). 
Fig. 12. Fig. 13. 

Aspects. 
Fig. 12, lateral; 13, heemal. 
one fifth of the antero-posterior extent of the neural platform. (The specimen figured 
is from a higher and larger individual than the articulated skeleton.) 
The fourth cervical vertebra of Dinornis maximus (figs. 12, 13), representing, with 
increase of size, the proportional characteristics of the third, resembles that of the 
Ostrich in the greater production of the pleurapophysis, p/, and in the absence of the 
hypapophysis. 
The interzygapophysial plate, 7, not extending to the postzygapophysis, z, does not 
circumscribe the space forming the foramen, s, in figs. 8& 11; and the pneumatic 
foramen (fig. 12, pn) comes into view. The zygapophysial articulations, z, z, become 
elongated; the posterior outlets of the vertebrarterial canals expand. 
There is little, if any, modification of the pre- or post-axial articular surfaces (ae, pe) 

